Electric circuit breaker with auxiliary trip mechanism

ABSTRACT

An electric circuit breaker having a circuit closing mechanism including a rotary drive shaft movable in opposite pivotal directions and a cam movable by the drive shaft along a predetermined path in one direction to effect a closed circuit condition across the breaker is provided with an auxiliary trip actuating mechanism associated with the rotary shaft. The auxiliary trip actuating mechanism includes a trip drive plate mounted on the drive shaft for movement therewith in opposite pivotal directions and a trip arm mounted on the cam for pivotal movement between a retracted position and a tripping position, the trip arm being responsive to movement of the trip drive plate in a direction opposite said one direction to drive the trip arm toward its tripping position when the breaker is in a closed circuit condition.

Jencks et al.

Nov. 12, 1974 1 ELECTRIC CIRCUIT BREAKER WITH AUXILIARY TRIP MECHANISM [75] Inventors: Charles L. Jencks, Avon; Frank H.

Murphy, West Hartford, both of Conn.

[73] Assignee: General Electric Company, New

York, NY.

[22] Filed: July 30, 1973 [21] Appl. No.: 383,554

[52] U.S. Cl. 200/153 L, 200/50 A [51] Int. Cl. H0lh 3/32 [58] Field of Search 200/153 G, 153 H, 153 L, 200/153 LB, 50 A, 50 AA, 17, 18, 153 R,

[56] References Cited UNITED STATES PATENTS 3,343,109 9/1967 Jencks et al. 337/54 X 3,382,331 5/1968 Jencks et al. 200/50 A Murphy et al. 335/20 Bould et al. 200/153 LB X Primary ExaminerJames R. Scott [57] ABSTRACT An electric circuit breaker having a circuit closing mechanism including a rotary drive shaft movable in opposite pivotal directions and a cam movable by the drive shaft along a predetermined path in one direction to effect a closed circuit condition across the breaker is provided with an auxiliary trip actuating mechanism associated with the rotary shaft. The auxiliary trip actuating mechanism includes a trip drive plate mounted on the drive shaft for movement there'- with in opposite pivotal directions and a trip arm mounted on the cam for pivotal movement between a retracted position and a tripping position, the trip arm being responsive to movement of the trip drive plate in a direction opposite said one direction to drive the trip arm toward its tripping position when the breaker is in a closed circuit condition.

10 Claims, 6 Drawing Figures ELECTRIC CIRCUIT BREAKER WITH AUXILIARY TRIP MECHANISM BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates generally to high current capacity circuit breakers of the type employing a rotary or twist type handle requiring repetitive actuation to effect a closed circuit condition thereacross. More particularly, the present invention relates to a new and improved circuit breaker of the type described having an auxiliary manual trip actuating mechanism associated with and operated by the rotary-type handle.

Due to the high contact pressure required by circuit breakers of substantial current carrying capacity it has been necessary to provide rotary handle mechanisms of the repetitive ratcheting type to move the circuit breaker contacts to a closed circuit position. Typical of such circuit breakers are those disclosed in U.S. Pat. Nos. 3,343,109 and 3,382,331. The breaker conventionally is tripped either electrically as a result of an overload condition or manually by actuating a separate trip button. However, manual tripping of the breaker frequently must be conducted under emergency condi tions and the natural tendency of the operator is to grasp the relatively large actuating handle rather than depress the separate trip button in order to effect the tripping operation.

Accordingly, it is an object of the present invention to provide a new and improved auxiliary manual trip actuating mechanism associated with the rotary handle of the circuit breaker to provide an alternative method of manually causing an open circuit condition across the breaker.

In some ratcheting type devices, the handle is permitted to move away from the ON position to the first ratchet engaging position while the breaker remains closed. This permits the operator to exert a high force on the locking mechanism that could cause breakage or lock the handle in an intermediate position. However, in accordance with the present invention, movement of the handle toward the first ratchet engaging position, is effective to actuate the auxiliary trip operating mechanism not only to effect tripping of the breaker but also to avoid the application of high force to the locking mechanism or cause locking thereof in an intermediate position.

Another feature of the present invention is to provide the foregoing advantages without locking the handle and yet retaining the cam locking feature of U.S. Pat. No. 3,382,331 so as to avoid the problem associated with undesirable acceleration of the cam and the problem of overriding as set forth in that patent.

A further object of the present invention is to provide a rotary handle mechanism of the type described that utilizes a plurality of handle operations through arc segments of about 120 in order to set the breaker to its ON position, yet requires only a single operation of the same handle through an arc segment of substantially less than 120 in order to effect tripping of the breaker.

A still further object of the present invention is to provide a new and improved circuit breaker as the type described that provides two separate, distinct and independent methods of manually opening the breaker in an emergency situation.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

These and related objects are accomplished in accordance with the present invention by providing an electric circuit breaker with a circuit closing mechanism including drive means movable in opposite pivotal directions and a cam movable by the drive means along a predetermined path in one direction to effect a closed circuit condition across the breaker. The breaker includes a tripping mechanism for opening the circuits controlled by the breaker including a manual auxiliary trip actuating mechanism operatively associated with the drive means for operating the tripping mechanism upon pivotal movement of the drive means in a direction opposite said one direction. The auxiliary trip actuating mechanism includes a trip drive member mounted for movement with the drive means in opposite pivotal directions and a trip arm mounted for pivotal movement between a retracted position and a tripping position, the trip arm being responsive to movement of the trip drive member in a direction opposite said one direction to drive the trip arm toward its tripping position when the breaker is in a closed circuit condition.

A better understanding of the invention will be obtained from the following detailed description and the accompanying drawing of an illustrative embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a side elevation view, partially broken away and partially in section, of the handle portion of an electric circuit breaker incorporating the features of the present invention;

FIG. 2 is an enlarged plan view of a rotary handle mechanism for a circuit breaker including an auxiliary trip actuating assembly in accordance with the present invention, illustrating the position of moving elements thereof when the circuit breaker is in a tripped or OFF condition.

FIG. 3 is a plan view similar to FIG. 2 showing the position assumed by the moving elements of the handle mechanism after the drive cam for closing the breaker has been rotated through a first rotary step of FIG. 4 is a plan view of a segment of the mechanism shown in FIG. 3 illustrating the locked interengagement between the drive shaft and the cam locked member immediately prior to rotation of the. cam through the third and final rotary step of 120 or less.

FIG. 5 is a plan view similar to FIGS. 2 and 3 illustrating the position assumed by the moving elements of the handle mechanism after the cam has been rotated through its final step and the circuit breaker is in a closed circuit position and;

FIG. 6 is a plan view similar to FIG. 5 showing the position of the auxiliary trip assembly upon rotation of the handle to a tripping condition and just prior to opening of the circuit breaker.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring now to the drawings in greater detail wherein like reference numerals indicate like parts throughout the several figures, the invention is illustrated as embodied within an electric circuit breaker, indicated generally by the numeral 10, comprised of an insulating casing or housing having a lower or main body portion 12 and an upper or cover position 14 adapted to rest on the main body portion and fully enclose the operating mechanism of the circuit breaker. Although the specific operating mechanism of the circuit breaker may vary for purposes of illustration it may be considered as substantially identical to that described in greater detail in US. Pat. Nos. 3,343,109 and 3,382,331 and the disclosures therein are incorporated herein by reference. As mentioned in those patents, the separable contacts (not shown) are controlled for movement between a closed circuit position and an open circuit position by means of a releasable latch responsive both to an overload condition in the circuits controlled by the circuit breaker and to a manual push rod and trip button, such as the rod 16 extending through the cover portion 14 and provided with a manually actuated trip button 18.

As described in the aforementioned patents, the circuit breaker is moved to a closed circuit position by suitable reclosing means including a resetting and reclosing lever 20 responsive to repeated pivotal or cranking action of the main handle 22. The lever 20 is mounted in operative relationship with the releasable latch and the contacts as well as with the contact drive springs (not shown) whereby the lever 20 will move the releasable latch into a reset or latched condition while holding the contacts open and then will permit rapid closing of the contacts under the driving force of the contact drive springs.

As shown, the rotary handle mechanism of the circuit breaker includes a main drive shaft 24 mounted with the casing and rotatably supported therein in much the same manner as described in US. Pat. No. 3,382,331 so that the uppermost end portion thereof extends outwardly of the circuit breaker cover 14 and mounts an exposed manually operated handle 22 secured thereto so that it rotates with the main drive shaft 24. A flat cam plate 26 is rotatably mounted on the main drive shaft 24 and is operatively connected thereto through a spring biased pawl assembly 28 for step-wise ratcheting and one-way driving operation by the shaft 24 in a clockwise direction as viewed in FIG. 2. A second generally circular plate 30 of lesser circumference than the cam 26 is fixedly supported on the cam in spaced axial relationship thereto to sandwich the drive pawl assembly 26 therebetween for engagement with teeth or shoulders (not shown) on the main drive shaft 24. The reclosing lever 20 is constantly biased toward the peripheral cam surface 32 of the disclike cam 26 which is configured so as to slowly drive the reclosing lever radially outwardly to effect latchable resetting of the releasable trip latch of the breaker and then suddenly release the reclosing lever to permit closing of the separable contacts of the breaker in a rapid manner. Reference may be had to US. Pat. No. 3,343,109 for a more detailed description of the operation of the reclosing cam.

The main drive shaft 24 of the breaker is provided with a peripheral slot 34 immediately above the plate 30. A generally triangular cam lock member 36 having a notched shoulder portion 38 adjacent one corner thereof is mounted on the plate 30 for pivotal movement of the shoulder into and out of the slot 34 under the biasing influence of a tension spring 40. The cam lock member 36 is constantly biased in a clockwise direction as viewed in FIG. 2 by the spring 40 for driving the shoulder 38 into slot 34 to lock the cam against clockwise movement relative to the shaft and prevent overriding of the cam as the reclosing lever 20 is suddenly released to cause the desired closed circuit condition.

In order to reset the circuit breaker in a closed circuit condition, the rotary handle assembly must be moved from the tripped position shown in FIG. 2 to the closed circuit position shown in FIG. 5 against the force of the strong contact arm drive spring (not shown). This is accomplished by rotating the cam 26 in a clockwise direction as viewed in FIG. 2 via a ratcheting type actuation of the handle 22 and shaft 24 through a plurality of arc segments. The use of the ratcheting advance of the cam permits use of the breaker in confined spaces restricting full rotation of the handle while effecting full rotation of the cam. As shown in the drawing, the cam 26 is provided with a peripheral caming surface 32 of in creasing radius in a counterclockwise direction from a notch 44 adapted to receive the resetting and reclosing lever 20. In the tripped position, lever 20 assumes the position shown in FIG. 2 and bears against the cam lock member 36 against the bias of its tension spring 40 so as to hold the locking shoulder 38 out of engagement with the slot 34 in the central drive shaft 24. When closing the circuit breaker from this tripped position the operator first rotates the main handle 22 and shaft 24 counterclockwise to the next ratchet position. The cam 26 is held in the position shown in FIG. 2 by the lever 20 during the counterclockwise movement of the main drive shaft 24 and then, as the shaft is rotated in a clockwise direction, the shaft imparts similar rotation to the cam 26 to move the cam and the parts carried thereby to the position shown in FIG. 3. During this first 120 rotation of the cam, the cam lock member which is mounted on the plate 30, is also rotated and thus is no longer biased against the reclosing lever 20 but is urged into engagement with the main drive shaft 24 by its tension spring 40. However, the slot 34 is no longer in confronting relationship with the shoulder 38 so that no locking action occurs therebetween.

Next the handle 22 is again moved counterclockwise 120 to the next ratchet position and returned thereby moving the parts clockwise to a position 120 from that shown in FIG. 3. As the cam 26 is rotated in this manner, the reclosing lever 20 is forced radially outwardly from the main drive shaft 24 by the increasing radius of the caming surface 32. Following this, a third counterclockwise movement of 120 by the main drive shaft 24 will bring the notch 34 into registry with the locking shoulder 38 (FIG. 4) and the spring 40 will drive the cam lock member 36 clockwise thereby locking the cam 26 to the center drive shaft as the cam is moved in a clockwise direction along the last 120 segment of the cams rotation. During this last segment, the reclosing lever resets the releasable latch in a latched condition so that as the reclosing lever 20 reaches the notch 44 in the cam plate 26, a reset and latched condition has been effectuated within the mechanism.

When the cam plate rotates so as to bring the notch 44 into registry with the reclosing lever 20, the lever rapidly drops into the recess to cause a closed circuit condition across the circuit breaker. When the reclosing lever enters the notch 44 it moves the cam locking member 36 counterclockwise against the bias of its spring 40, moving the shoulder 38 out of a locked position with the main drive shaft 24 so that the mechanism assumes the position shown in FIG. 5. Unlike the cam locking member described in U.S. Pat. No. 3,382,331 the member 36 illustrated herein fully releases the main drive shaft 24 when the circuit breaker moves into a closed circuit condition, thus releasing the main drive shaft for further counterclockwise movement by the handle 22.

As best illustrated in FIG. 1 the circuit breaker is provided with a trip rod 16 operatively associated with thereleasable resetting latch of the circuit breaker. The trip rod 16 extends through the cover 14 of the casing and is provided with a manually operable trip button 18 which can be readily depressed to cause release of the releasable latch and effect tripping of the circuit breaker in a manner similar to that described in U.S. Pat. No. 3,343,109. As shown this manually actuated trip button 18 is independent of the main rotary handle 22 of the circuit breaker.

In accordance with the present invention an auxiliary manual trip mechanism is further provided in operative association with the rotary handle 22 and shaft 24 of the circuit breaker. The auxiliary mechanism includes a trip drive plate 46 mounted on the main drive shaft 24 for rotary motion therewith in both a clockwise and counterclockwise direction as viewed in FIGS. 5 and 6. The trip drive plate 46 is axially spaced above the cam lock member 36 and extends radially outwardly from the drive shaft in a fully circumscribing manner so as to be constantly positioned between a pair of guide plates 48 mounted on plate 30 in an elevated or spaced position relative thereto. The guide plates 48 are fixedly mounted on the plate 30 and move with the cam 26 through its three l rotational segments. The trip drive plate includes a drive segment 50 having a drive face 52 extending outwardly from the drive shaft in radial fashion and an arcuate retaining surface 54 of constant radius extending in a clockwise direction as viewed in FIG. 5 from drive face 52 through an arc segment of about 135.

Also mounted near the edge of plate 30 adjacent guide plates 48 is a pivotal trip arm 56 supporting a shouldered pin 58 on one end thereof and a depending trip actuating flange 60 on the opposite end thereof. Since the trip arm 56 is mounted on the plate 30 it also will travel with the cam 26 during its segmented rotational movement. As illustrated the trip arm 56 is pivotally mounted at about its midpoint and the flange 60 extends well below plate 30 but does not reach cam 26. The arm 56 is constantly biased in a counterclockwise direction by a tension spring 62 and the plate 30 is provided with a notch 64 into which the depending flange 60 of the trip arm is drawn under the counterclockwise bias force of the spring 62.

The trip rod 16 of the circuit breaker is shown a being provided with a fixedly mounted actuator lever 66 that extends laterally of the rod and tangentially of cam 26 to a point radially inwardly of the caming surface 32 intermediate the cam 26 and the overlying plate 30. The depending flange 60 of the trip arm is provided with a slanted or caming free end surface 68 (see FIG. 1) adapted to contact ride over the lever 66 to drive the lever downward and effect tripping of the circuit breaker.

As mentioned hereinbefore, the moving elements of the rotary handle mechanism assume the position depicted in FIG. 5 when the circuit breaker is in a closed circuit operating condition. As shown in FIG. 5, the trip arm 56 is fully retracted by spring 62 so that the depending flange 60 is within notch 64 and the shouldered pin 58 on the opposite end thereof is in contact with the drive face 52 of the trip drive plate 46. Additionally, as mentioned hereinbefore, the reclosing lever 20 is within cam notch 44 thereby preventing rotational movement of the cam 26 and is holding cam lock member 36 in a released position relative to the main drive shaft 24 against the bias of spring 40 so that the shaft 24 is free to rotate in a counterclockwise direction. As the handle 22 and shaft 24 are moved counterclockwise, the trip drive plate 46 will also move counterclockwise with its drive face 52 bearing against the shouldered pin 58 to drive the trip arm 56 clockwise against the bias of its tension spring 62. The clockwise movement of the trip arm brings the slanted cam surface 68 on the free end of flange 60 into engagement with the trip actuator lever 66, driving the lever and attached trip rod 16 downwardly to effect tripping of the circuit breaker.

As will be noted, when the rotatable drive shaft 24 moves from the closed circuit position illustrated in FIG. 5, to the tripping position illustrated in FIG. 6, the handle is moved through a substantially smaller counterclockwise arc segment than is required to move the shaft to its next ratchet engaging position. In fact, a counterclockwise movement of only about 40-50 is required to fully depress lever 66 and provide the desired tripping action.

It is an advantageous feature of the present invention that movement of the main handle 22 in a counterclockwise direction while the breaker is in its closed circuit condition will effect tripping of the circuit breaker thus assuring that an excessively high force is not applied to the rotary handle mechanism to cause jamming or breaking thereof or locking in an intermediate position. Additionally, the arc segment movement required for the tripping operation is substantially less than that required for moving the main drive shaft 24 to its next ratchet engaging position. It will, of course, also be appreciated, that if the breaker mechanism is already in a tripped condition with the moving elements of the rotary handle mechanism in the position shown in FIG. 2, the shaft 24 may be rotated 360 in a clockwise direction to reach the position of FIG. 5 or the cam may be incrementally advanced along the same path via the ratcheting operation described hereinbefore. In the case of the 360 clockwise rotation of the shaft 24, the flange 60 will remain in notch 64 and will bypass lever 66 without effecting movement thereof. In the case of step-wise advancement of cam 26, the initial counterclockwise movement of the handle 22 and drive shaft 24 will automatically depress the lever 66 and trip rod 16 to assure the tripped condition of the breaker as the main drive shaft is moved to its first ratchet engaging position. As best shown in FIG. 3, the arcuate retaining surface 54 of the trip drive plate 46 will continue to engage the shouldered pin 58 during the first full rotation of the main drive shaft 24 so that the trip arm 56 assumes the position shown in FIG. 3 and maintains that position during the first step in the clockwise movement of the drive cam 26. This clockwise movement of the cam 26 rotates the trip arm 56 away from the trip lever 66 so that upon release of the trip arm, its counterclockwise movement under the return bias of the tension spring 62 will merely return it to its retracted position without contacting the lever 66 affixed to the trip rod. In this connection, it should be noted that the release of the trip arm by the trip drive plate will occur upon the counterclockwise movement of the main drive shaft 24 during its second 120 ratchet step. However, as will be appreciated, return of the trip arm to its retracted position at any time prior to the final stepwise movement of the cam 26 will be satisfactory to-return the mechanism to the desired position prior to the circuit breaker assuming its closed circuit condition. Additionally, the locking engagement between shoulder 38 and notch 34 prevents release of the shaft 24 after only partial movement of cam 26 along the third and final portion of its contact closing motion.

Thus, as can be seen from the foregoing detailed description, the auxiliary trip actuating mechanism of the present invention provides an additional separate and independent manual means for tripping the circuit breaker. This means is associated with the operation of the main handle of the circuit breaker and takes advantage of the operators natural tendency to grasp that main handle in an emergency situation. The auxiliary tripping mechanism requires substantially less than a 120 stepwise movement of the handle even though three operations of l are required to move the circuit breaker to its closed circuit position. Additionally, the mechanism in no way interferes with the separate manual trip button but is complimentary thereto and provides an alternative means for opening the breaker. Further, the mechanism retains a positive antioverridding feature but immediately releases the handle for'further actuation while obviating the possibility of the operator applying excessive force to the mechanism or causing locking in an intermediate position.

As will be apparent to persons skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the teachings of the present invention.

We claim:

1. In an electric circuit breaker having a circuit closing mechanism including a cam movable along a predetermined path to effect a closed circuit condition across the breaker, drive means movable in opposite pivotal directions and operatively connected to the cam upon movement in one direction to drive the cam in said one direction along said path, and a tripping mechanism including a manual trip actuator for opening the circuit controlled by the breaker, the combination including an auxiliary trip actuating mechanism operatively associated with said drive means for operating the tripping mechanism comprising a trip drive member connected to said drive means for conjunctive movement in opposite pivotal directions and a trip arm mounted for pivotal movement between a retracted position and a tripping position, the trip drive member engaging said trip arm upon movement with said drive means in a direction opposite said one direction to drive the trip arm toward it tripping position when the breaker is in a closed circuit condition to "initiate tripping of the breaker.

2. The circuit breaker of claim 1 including biasing means connected to the trip arm for urging the latter into engagement with the trip drive member for controlling movement of the trip arm between its retracted and tripping positions.

3. The circuit breaker of claim 1 wherein the trip arm is mounted by the cam of the closing mechanism for movement therewith, said cam, upon effecting a closed circuit condition across the breaker, automatically positions said tripping arm to operatively engage the tripping mechanism upon movement of the tripping arm to its tripping position.

4. The circuit breaker of claim 1 wherein the drive means includes a rotatable drive shaft and the trip drive member is a drive plate mounted on the shaft for movement therewith in opposite pivotal directions, said cam rotatably mounted on the shaft in spaced axial relationship with the drive plate.

5. The circuit breaker of claim 1 wherein the trip actuator is slidably movable toward a tripping position and the trip arm includes a cam face for engaging said slidably moving the trip actuator toward its tripping position upon movement of the trip arm toward its tripping position.

6. The circuit breaker of claim 1 wherein the drive means includes a shaft, the trip drive member is a plate secured to the shaft for movement therewith, the auxiliary trip mechanism includes spring means urging the trip arm toward a retracted position, the trip arm being mounted by the cam for movement therewith under the driving action of the shaft and being provided with a pin on one end thereof engageable by the plate upon rotation of the shaft in a direction opposite said one direction when the cam is in a closed circuit position to drive the trip arm out of the retracted position against the bias of the spring means.

7. The circuit breaker of claim 1 wherein the trip actuator is depressed for effecting tripping of the breaker, the trip arm is mounted by the cam for pivotal movement toward and away from a tripping position in response to engagement by said trip drive member and includes an inclined cam surface operative against the trip actuator to depress the actuator as the trip arm is driven toward its tripping position.

8. In a rotary handle mechanism comprising a cam having a cam surface mounted for rotary movement in a first direction along a predetermined path, cam operating means including one-way drive means for driving the cam in said first direction, a cam follower engaging the cam surface for movement in response to rotary movement of the cam and locking means operatively interconnecting the cam and the cam operating means to prevent relative movement therebetween during only the final portion of the rotary movement of the cam, the combination including an auxiliary trip assembly operatively associated with the cam operating means comprising trip actuating means mounted for pivotal movement toward and away from a trip actuating position, a trip drive member mounted for movement with the cam operating means, said cam follower being operative upon completion of the final portion of the movement of the cam along said predetermined path to engage said locking means and release the cam operating means for movement relative to the cam, said trip drive member being movable in a direction opposite said first direction by the cam operating means upon release of the cam operating means for driving the trip actuating means toward the trip actuating position.

l0 ased away from a trip actuating position, the trip drive member including a drive face engageable with the trip actuating means for driving the trip actuating means toward a tripping position against its bias and a returning surface for holding the trip actuating means in its tripping position during the initial portion of the movement of the cam along said predetermined path.

zg g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, g Dated November 12, 1974 Inventor) Charles L. Jenc ks and Frank H. Murphy It is certified that error appears in the above-identif'ied'patent and that said Letters Patent are hereby corrected as shown below:

At column 8, line 18, "s aid" should reed -an d -l At column 10, lines 4 and 5; "returning" hould reed -retaining Y Signed end see led'thisfith riey offeoruia ry 11975.

(SEAL) Attest:

YMcCOY M. GIBSON JR. v r d. MARSHALL DA I Attesting Officer Comissioner of Patente- 3 UNITED-STATES PATENT OFFICE 4 CERTIFICATE OF CORRECTION .Patent No. 3,848 1O2 I Dated November 12, 1974 Inventor) Charles L. Jenclcs and Frank H. Murphy It is certified that error appears in the above-identified-patent and that said Letters Patent are hereby corrected as shown below:

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McCOY M. GIBSON JR. w CQ RSHALL DANN; Atteating Officer Commissioner of Patent; 

1. In an electric circuit breaker having a circuit closing mechanism including a cam movable along a predetermined path to effect a closed circuit condition across the breaker, drive means movable in opposite pivotal directions and operatively connected to the cam upon movement in one direction to drive the cam in said one direction along said path, and a tripping mechanism including a manual trip actuator for opening the circuit controlled by the breaker, the combination including an auxiliary trip actuating mechanism operatively associated with said drive means for operating the tripping mechanism comprising a trip drive member connected to said drive means for conjunctive movement in opposite pivotal directions and a trip arm mounted for pivotal movement between a retracted position and a tripping position, the trip drive member engaging said trip arm upon movement with said drive means in a direction opposite said one direction to drive the trip arm toward it tripping position when the breaker is in a closed circuit condition to initiate tripping of the breaker.
 2. The circuit breaker of claim 1 including biasing means connected to the trip arm for urging the latter into engagement with the trip drive member for controlling movement of the trip arm between its retracted and tripping positions.
 3. The circuit breaker of claim 1 wherein the trip arm is mounted by the cam of the closing mechanism for movement therewith, said cam, upon effecting a closed circuit condition across the breaker, automatically positions said tripping arm to operatively engage the tripping mechanism upon movement of the tripping arm to its tripping position.
 4. The circuit breaker of claim 1 wherein the drive means includes a rotatable drive shaft and the trip drive member is a drive plate mounted on the shaft for movement therewith in opposite pivotal directions, said cam rotatably mounted on the shaft in spaced axial relationship with the drive plate.
 5. The circuit breaker of claim 1 wherein the trip actuator is slidably movable toward a tripping position and the trip arm includes a cam face for engaging said slidably moving the trip actuator toward its tripping position upon movement of the trip arm toward its tripping position.
 6. The circuit breaker of claim 1 wherein the drive means includes a shaft, the trip drive member is a plate secured to the shaft for movement therewith, the auxiliary trip mechanism includes spring means urging the trip arm toward a retracted position, the trip arm being mounted by the cam for movement therewith under the driving action of the shaft and being provided with a pin on one end thereof engageable by the plate upon rotation of the shaft in a direction opposite said one direction when the cam is in a closed circuit position to drive the trip arm out of the retracted position against the bias of the spring means.
 7. The circuit breaker of claim 1 wherein the trip actuator is depressed for effecting tripping of the breaker, the trip arm is mounted by the cam for pivotal movement toward and away from a tripping position in response to engagement by said trip drive member and includes an inclined cam surface operative against the trip actuator to depress the actuator as the trip arm is driven toward its tripping position.
 8. In a rotary handle mechanism comprising a cam having a cam surface mounted for rotary movement in a first direction along a predetermined path, cam operating means including one-way drive means for driving the cam in said first direction, a cam follower engaging the cam surface for movement in response to rotary movement of the cam and locking means operatively interconnecting the cam and the cam operating means to prevent relative movement therebetween during only the final portion of the rotary movement of the cam, the combination including an auxiliary trip assembly operatively associated with the cam operating means comprising trip actuating means mounted for pivotal movement toward and away from a trip actuating position, a trip drive member mounted for movement with the cam operating means, said cam follower being operative upon completion of the final portion of the movement of the cam along said predetermined path to engage said locking means and release the cam operating means for movement relative to the cam, said trip drive member being movable in a direction opposite said first direction by the cam operating means upon release of the cam operating means for driving the trip actuating means toward the trip actuating position.
 9. The handle mechanism of claim 8 wherein the auxiliary trip assembly is mounted in spaced overlying relationship with the cam, the trip drive member is a plate mounted by the cam operating means and the trip actuating means includes a driven portion cooperatively engaged by the plate to drive the actuating means toward a trip actuating position.
 10. The handle mechanism of claim 8 wherein the trip actuating means is movable with the cam and is biased away from a trip actuating position, the trip drive member including a drive face engageable with the trip actuating means for driving the trip actuating means toward a tripping position against its bias and a returning surface for holding the trip actuating means in its tripping position during the initial portion of the movement of the cam along said predetermined path. 